Fluid seal



Patented Dec. 22, 1953 FLUID SEAL James R. C. Waterston, Edinburgh, Scotland, assignor to Brown Brothers & Co. Limited, Edinburgh, Scotland, a corporation of Great Britain and Northern Ireland Application November 30, 1950, Serial No. 198,279

Claims priority, application Great Britain July 10, 1950 (Cl. 18S-100) 3 Claims.

The subject of this invention is a fluid seal for retaining liquid in a cylinder open at one end against gravitational or other forces which tend to cause the liquid to oW out of the cylinder.

For convenience, the liquid will be referred to hereinafter as water, and the arrangement chosen for the purpose of the description will be that in which the cylinder is disposed horizontally.

An important one of the practical applications of the invention is in connection with catapults for launching aircraft wherein the retarding gear includes a cylinder laid horizontally at the end of the catapult rail With the open end of the cylinder towards the trolley.

The trolley or moving part of the catapult is provided with a tapered ram or like member which, at the beginning of the retardation stroke of the trolley or moving part, enters the cylinder which is full of water, and in so doing eXpels the water through the gap formed between the mouth of the cylinder and the ram or like member carried by the trolley, while setting up in the Water in the cylinder a high pressure which, acting on the area of the ram, provides the required retarding force.

According to the present invention the open end of the cylinder is sealed by a series of jets emerging from orifices disposed at the mouth of the cylinder and so directed relatively to the axis of the cylinder that the axis of each jet has an axial, a tangential, and a radial component.

To provide for the orientation of the jets, passages terminating in oriiices may lead from an annular chamber surrounding the cylinder near the mouth of the` cylinder, the passages being each disposed at a predetermined angle relatively to the axis of the cylinder and also at a predetermined angle relatively to the respective radius.

A practical embodiment of the invention is illustrated in the accompanying drawings in which Fig. 1 is a semi-diagrammatic longitudinal section of a cylinder having a fluid seal, and Fig. 2 is a section through the line 2-2 in Fig. 1.

In the drawings I denotes a cylinder filled with liquid 2. 3 denotes jets of uid emerging from passages l disposed around the mouth of the cylinder l, said passages 4 being in communication with an annular chamber 5. The passages are so orientated With respect to the axis of the cylinder l that they each have an axial, a tangential, and a radial component, the jet issuing from each passage thus having an axial, a tangential, and a radial component.

1n practice, the kinetic energy of the uid of the jets 3 is sufficient to hold the liquid 2 in the cylinder l against the natural tendency of the liquid 2 to run out of the cylinder under the influence of the force of gravity.

The jet orifices so provided are not liable to chokage and there is obtained full control of the relation between the quantity of water injected as influenced by the size and number of the orifices, the axial component of velocity being dependent on the inclination to the axis of the cylinder and the rotational velocity being dependent on the inclination of each orifice to its respective radius. Further, with the described arrangement the resultant jets are not liable to be affected by the choice of the means of supply of the Water to the annular chamber.

The supply pipes may enter the annular chamber tangentially in one direction or tangentially in opposite directions, or radially, in which case a single pipe or a multiplicity of pipes may be used.

In the operation of the apparatus according to the invention, a pump supplying Water under pressure to the chamber 5 is started up and in about three or four seconds the cylinder l is i'illed, except for the open mouth. The pressure is maintained continuously, and after the cylinder is filled, the surplus water runs out from the center of the region bounded by the jets. The surplus water drains into a tank from which it is continuously pumped back to the cylinder jets, maintaining the cylinder filled with Water. The jets of water provide a fluid seal which is maintained by the energy of the jets at the open end of the cylinder.

What is claimed is:

1. In a generally horizontally-disposed cylinder for use in retarding the movement of a ram having a closed end and an open end to receive the ram, means operatively associated with the open end of the cylinder for filling the cylinder with liquid and for maintaining liquid in the cylinder in opposition to the natural tendency of the liquid to run out of the cylinder, said means comprising walls defining a circular-shaped annular chamber at the mouth of the cylinder, the inner Wall of said chamber having a series of spaced passageways extending around said wall each leading from said chamber to the mouth of said cylinder, each passageway extending at an incline to and to one side of the axis of the cylinder and at an incline to a radius therefrom in a direction for directing a jet of liquid into the cylinder from its mouth at an angle to said radius and to one side of the axis of the cylinder,

3 the passageways of the series extending in the same direction with respect to said wall and the axis of the cylinder, and means for conducting liquid under pressure :into saidchamher for delivery through 'said'nassageways into said` cyliinder.

2. A generally horizontally-disposed cylinder as,V

claimed in claim 1, in which said inner Wall com;

prises a circular-shaped ring member through-'5i fv Y which said passageways extend.

3. In a generally horizontally-disposed, liquid@ containing cylinder, having., a,y clos'ec'end anchL an open end, liquid-injecting means at the open end of the cylinder comprising an annular wall defining a boundary of a chamber', said-l wallliavs into the mouth of said cylinder, the axis of each passageway being tangent to the surface of an imaginary cylinder co-aXial with said horizontally-disposed cylinder and lying wholly Within said horizontally-disposed cylinder and having a diameter l'es's, than the; internal diameter of said horizontally-disposed cylinder, said chamber having an inlet for uid under pressure.

JAMES R. C. WATERSTON.

References Cited in the le of this patent UNITED/STATES PATENTS Number. Name Date 13,521,399-`v Reynolds Dec. 30, 1924 2,307,694 Malke Jan. 5, 1943 v FOREIGN PATENTS Number Country Date 9,609 Great Britain 1915 

